The cinnamolyl-CoA esters, the precursors of monolignol biosynthesis, are generated by the general phenylpropanoid pathway and then converted into monolignols by two enzymes, cinnamoyl-CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD).Cinnamoyl-CoA reductase (CCR) represents the enzymatic entry step that leads into the monolignol-specific branch of the phenylpropanoid pathway in angiosperms  and this also applies to conifer species.Suppression of CCR in angiosperms resulted in lignin reductions of up to 50%, providing evidence for the crucial role of CCR in monolignol biosynthesis. CCR suppression in angiosperms also caused the incorporation of ferulate into the lignin polymer and changes in the metabolite profile.